/******************************************************************************
 * Qwt Widget Library
 * Copyright (C) 1997   Josef Wilgen
 * Copyright (C) 2002   Uwe Rathmann
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the Qwt License, Version 1.0
 *****************************************************************************/

#ifndef QWT_PLOT_GLCANVAS_H
#define QWT_PLOT_GLCANVAS_H

#include "qwt_global.h"
#include "qwt_plot_abstract_canvas.h"

#include <qgl.h>

class QwtPlot;

/*!
   \brief An alternative canvas for a QwtPlot derived from QGLWidget

   QwtPlotGLCanvas implements the very basics to act as canvas
   inside of a QwtPlot widget. It might be extended to a full
   featured alternative to QwtPlotCanvas in a future version of Qwt.

   Even if QwtPlotGLCanvas is not derived from QFrame it imitates
   its API. When using style sheets it supports the box model - beside
   backgrounds with rounded borders.

   Since Qt 5.4 QOpenGLWidget is available, that is used by QwtPlotOpenGLCanvas.

   \sa QwtPlot::setCanvas(), QwtPlotCanvas, QwtPlotOpenGLCanvas

   \note With Qt4 you might want to use the QPaintEngine::OpenGL paint engine
        ( see QGL::setPreferredPaintEngine() ). On a Linux test system
        QPaintEngine::OpenGL2 shows very basic problems like translated
        geometries.

   \note Another way for getting hardware accelerated graphics is using
        an OpenGL offscreen buffer ( QwtPlotCanvas::OpenGLBuffer ) with
   QwtPlotCanvas. Performance is worse, than rendering straight to a QGLWidget,
   but is usually better integrated into a desktop application.
 */
class QWT_EXPORT QwtPlotGLCanvas : public QGLWidget,
                                   public QwtPlotAbstractGLCanvas
{
  Q_OBJECT

  Q_PROPERTY(QFrame::Shadow frameShadow READ frameShadow WRITE setFrameShadow)
  Q_PROPERTY(QFrame::Shape frameShape READ frameShape WRITE setFrameShape)
  Q_PROPERTY(int lineWidth READ lineWidth WRITE setLineWidth)
  Q_PROPERTY(int midLineWidth READ midLineWidth WRITE setMidLineWidth)
  Q_PROPERTY(int frameWidth READ frameWidth)
  Q_PROPERTY(QRect frameRect READ frameRect DESIGNABLE false)

  Q_PROPERTY(double borderRadius READ borderRadius WRITE setBorderRadius)

public:
  explicit QwtPlotGLCanvas(QwtPlot * = NULL);
  explicit QwtPlotGLCanvas(const QGLFormat &, QwtPlot * = NULL);
  virtual ~QwtPlotGLCanvas();

  Q_INVOKABLE virtual void invalidateBackingStore() QWT_OVERRIDE;
  Q_INVOKABLE QPainterPath borderPath(const QRect &) const;

  virtual bool event(QEvent *) QWT_OVERRIDE;

public Q_SLOTS:
  void replot();

protected:
  virtual void paintEvent(QPaintEvent *) QWT_OVERRIDE;

  virtual void initializeGL() QWT_OVERRIDE;
  virtual void paintGL() QWT_OVERRIDE;
  virtual void resizeGL(int width, int height) QWT_OVERRIDE;

private:
  void init();
  virtual void clearBackingStore() QWT_OVERRIDE;

  class PrivateData;
  PrivateData *m_data;
};

#endif
